The present invention relates to a magnetic disk drive and, more particularly, to a magnetic disk drive improved to reduce the influence of a tension ascribable to the forming of a flexible printed circuit, which transfers the output signal of a magnetic head, on a carriage.
A conventional magnetic disk drive has a carriage in the form of an arm and rotatably mounted on a shaft. A suspension is affixed to the free end of the carriage and in turn supports a magnetic head at the free end thereof. A coil assembly is affixed to the rear end of the carriage while a permanent magnet assembly is located to face the coil assembly. A control circuit positions the carriage which is rotated by an electromagnetic force generated between the coil assembly and the permanent magnet assembly. A flexible printed circuit (FPC) is connected at one end to the carriage and at the other end to the base of the disk drive for transferring the output signal of the head to the control circuit. The problem with the conventional magnetic disk drive is that the radius of curvature of the FPC noticeably changes depending on the position of the head in the radial direction of the disk. As a result, the tension acting on the FPC greatly changes. Since the tension acts on the carriage and constantly changes during the course of seek, even the servo loop fails to position the head with accuracy, resulting in a seek error or a read error.